Rice (Oryza sativa) is the second most important staple crop in the world and has originated in a tropical region and 90 per cent of the rice is produced and consumed in S. E. Asia. About 85% of the most common rice consumed by humans is white rice and the rest is pigmented rice. The pigmented rice is mainly black, red and dark purple rice, which have dark red, dark purple, dark blue, red brown, black purple, or dark red-purple grains. The pigmented rice has been consumed in China, Japan, and Korea and it is widely known as enriched rice for taste and health improvements.
September 1st 2022, 5:42:42 pm | 5 min read
Rice (Oryza sativa) is the second most important staple crop in the world and has originated in a tropical region and 90 per cent of the rice is produced and consumed in S. E. Asia. About 85% of the most common rice consumed by humans is white rice and the rest is pigmented rice. The pigmented rice is mainly black, red and dark purple rice, which have dark red, dark purple, dark blue, red brown, black purple, or dark red-purple grains. The pigmented rice has been consumed in China, Japan, and Korea and it is widely known as enriched rice for taste and health improvements. Even though India stands, second largest in the production of rice, cultivation of pigmented rice is restricted to some parts of Northeast and in Western Uttar Pradesh, Punjab, and Gujarat etc. The pigmented rice produced in India were black rice, red rice and purple rice. Generally, different types of rice are named according to their physical appearance of the rice bran. The color of the rice bran differs due to the presence of pigments in the rice varieties. All three pigmented rice are unique in its functional properties and have different pigment concentration. The compounds responsible for these color variations are the flavonoids anthocyanin and proanthocyanidin, which are known to have nutritional value. Pigmented rice consists of flavones, tannin, phenolics, sterols, tocols, γ -oryzanols, amino acids, and essential oils. But due to lack of production and awareness about pigmented rice’s thearapeutical benefits white rice is more popular than pigmented rice in India.
Pigmented rice has numerous health benefits. Pigmented rice grain possesses anti-oxidant, anti-diabetic, anti-hyperlipidemic, and anti-cancer activity. Due to its high secondary metabolite contents and high antioxidant activity, pigmented rice is used in the manufacture of commercial healthy food supplements. It also has the potential of boosting kidney function, treating, healing anaemia, stimulate blood circulation and treating diabetes. According to WHO recommendations, rice-based ORS is reported to be better than glucose based ORS. Indian pharmacopoeia recommends pigmented rice drinks (chilled) excellent for inflammatory diseases and diarrhea. The primary pigment which is present in the rice bran, Anthocyanin not only responsible for its colour but it also enhances the antioxidant activity, anticancer, and hypoglycaemic effects.
China and India are the major producers of black rice, followed by Thailand, Bangladesh, Vietnam, and Indonesia. It consists of many rice varieties with an extensive historical background on cultivation in Southeast Asian countries such as China, India, and Thailand. The pigment present in the rice bran Anthocyanin (cyanidin-3-glucoside) turns the color of the rice to black color. Anthocyanin is secondary metabolites of the flavonoid formed due to environmental stress. The darker color of rice, with higher anthocyanin content and antioxidant makes high potential of rice as a functional food. Black/purple rice exhibits higher amounts of Fe, Zn, Ca, Cu and Mg than red rice. In India, black rice is used as a dietary supplement for the treatment of various diseases such as diabetes, cancer, lipid disorders, and gastrointestinal diseases. Black rice contains superior protein and essential amino acids compared with ordinary rice. Amino acids play a vital role in body development via protein metabolism. Excess amino acids are converted into ammonia by the removal of the amine group in the liver. They play a key role in an individual's diet in modifying risk to pre-diabetes. Black rice has been proven scientifically for its various pharmacological activities. Research has also confirmed the antioxidant activity, antitumor, anti-inflammatory antiproliferative, anticancer, anti-diabetes and hyperlipidemia, and anti-atherosclerosis activity of black rice, the cholesterol and lipid metabolism and the tyrosinase inhibitor activity.
Red rice is a variety of rice that is colored red by its anthocyanin content. It is usually eaten unhulled or partially hulled, and has a red husk, rather than the more common brown. Red rice has a nutty flavor. Compared to polished rice, it has the highest nutritional value of rice. Red rice, also known as weedy rice is a low-yielding rice variety that persists as a weed in fields of better quality rice. It has anthocyanin in its pericarp accounting for its colour. Ayurvedic as well as allopathic medical practitioners recommend raw red rice for diabetics. It has phenolic compounds in the range of 165.8–731.8 mg gallic acid equivalent per 100 g.
Pigmented rice is more beneficial and therapeutic than the white rice but people are slowly becoming aware with its uses and importance. It needs to be incorporated in daily diet to see its complete beneficial as a functional food. It is an excellent source of vitamins and minerals which are very essential by our body. It can be fortified in other instant food products to boost their nutrition profile. Though its production and consumption has grown in some parts of the world but still it doesn’t reached up to its full capacity. If the production of these rice increases and awareness would be spread using all media about its benefits, we can help in reducing health related problems and minimise the use of artificial medicines.
College of Agriculture, Central Agricultural University (Imphal), Pasighat
College of Horticulture & Forestry, Central Agricultural University (Imphal), Pasighat